Aerodynamic performance of improved shallow π shape bridge deck

Aerodynamic stability of π section, which is structurally economical, was studied. By locating the main girders at inward location, so that the ratio of the floor deck overhang C to the girder height D′, C/D′, to be 2.0, and also setting solid barriers at inward location, the wind-induced responses were much suppressed even under various angles of attack. Although, some wind-induced responses were still observed with the improved section, the magnitude of the negative aerodynamic damping that caused the vibration was found to be small, thus the section could be thought as a probable choice for long-span bridges. The stability due to the solid barrier location was accomplished by the separated flows mutual interference effect; the unsteady pressure on the upper surface of the deck decreased significantly for the torsional motion.